Frusto-conical shaped wire baskets are well known for use in containing the root ball of a tree or shrub. Equipment for digging and balling generally includes a plurality of spades which are positioned around the base of the tree which is to be transplanted. The spades are then activated to dig down into the earth around the tree roots and lift the tree out of the ground. When the tree is lifted, the earth is simultaneously compacted into a ball around the roots, and the ball is then placed in a container for transporting. Such equipment is disclosed in U.S. Pat. Nos. 3,618,234 and 3,713,234.
Various types of containers have been utilized to maintain the tree ball and protect the root system of the tree. Such containers must maintain the tree ball in a compact state, as free as possible from cracks, and should be of minimal weight to reduce shipping costs and difficulties in handling, and are preferably transplanted with the tree. In meeting at least the above standards, wire baskets have become the container preferred by many nursery operators. However, certain disadvantages exist with baskets currently in use and in their manufacture.
A first problem is associated with the manufacturing of the wire baskets. Because of the pluralities of wire elements which must be welded together to make one basket, the conventional manufacturing method is expensive. The circular rings are first made and then welded to upright side wires or loops in a time-consuming operation wherein much of the welding is performed one joint at a time.
Additionally, the type of wire used in the baskets is unsatisfactory. Known manufacturing methods utilized a galvanized wire for the baskets. Galvanized wire does not bend easily, when bent does not take a set, and it is therefore difficult to make any adjustments to the basket to tighten it around the root ball if desired. Further, galvanizing is the coating of metal to prevent or inhibit rusting. As a result galvanized wire baskets require a long period of time for corrosion and breaking down of the wire to occur. A galvanized wire basket can take as long as twenty years to corrode and disintegrate. While the roots of the tree can of course grow over and through the wires of the basket, the growth process is improved if the basket is rapidly disintegrated. Additionally, as the basket corrodes it fertilizes the tree. Thus rapid corrosion of the wire is advantageous for a number of reasons.
The present invention is directed to a wire basket and the method and apparatus for making the baskets at approximately one-third of the previously known cost. In addition to more economical production methods, the wire baskets according to a preferred embodiment are made of annealed wire rather than galvanized. The use of annealed wire allows the side wires or loops of the basket to be twisted or bent as necessary to tighten a basket around the tree ball. Further, after the tree is transplanted, the uncoated annealed wire quickly corrodes and disintegrates within a period of weeks or months rather than years. As the basket corrodes, the disintegrating metallic elements provide nutrients to the soil in the early stages of tree growth.
A second similar type of tree basket is designed to support tomato vines. The tomato basket is generally of a taller height and smaller diameter than the tree baskets. Further, in constructing the tomato baskets, straight vertical sidewires are welded to the arcuate segments, rather than vertical wire loops as utilized in the tree baskets. Otherwise, construction methods for the tree and tomato baskets are the same. The tomato basket is also a truncated conical shape tapering inwardly from top to bottom of the basket, with the bottom of the basket having an angle of approximately 85.degree. to the horizontal plane.
The construction method for both types of wire baskets involves the use of a unique welding fixture for first forming a basket flat, which flat is then subjected to a bending operation to impart the desired conical shape to the finished basket.
The welding fixture comprises a flat wooden board preferably cut into a 180.degree. semicircular shape and having a planar top surface. The board is adapted to be rotatably mounted between the electrodes of a conventional welding machine (known as cross wire resistance welding or projection welding) for welding a plurality of wire pieces together to form the basket flat. The upper planar surface of the welding fixture includes a pattern of arcuate grooves for receiving the lengths of wire which ultimately become the circular rings of the basket; and a plurality of loop-shaped or straight grooves which receive the wire loops or members that form the upright side portions of the basket. The arcuate grooves are cut into the welding board in a pattern wherein the outer groove is of one radius, and the arcuate grooves which lie in concentrically spaced relationship to each other toward the mid-portion of the welding board are of constantly decreasing radii; the smallest arc lying closest to the pivot point of the board which is at the center of the straight edge.
The grooves which receive the wire loops or members are positioned in arcuately spaced relationship to each other and extend along substantially radial grooves intersecting the arcuate grooves. In use, straight lengths of wire, which will form the circular rings of the finished basket, are laid in the arcuate grooves and the closed wire loops or straight members are placed in the radial grooves, overlying the arcuate wires. The welding fixture is then pivoted to a plurality of stops between the electrodes of the welding element which welds the connecting members to the arcuate wires at each intersecting point. After the welding operation is completed the basket flat is removed from the welding fixture and forwarded to the next operation.
The next step in production is subjecting the basket flat to a bending machine such as a pinch roller mechanism. When the basket flat is run through the bending machine it bends into a conical shape such that the ends of each of the arcuate wires are substantially face to face, forming a circular ring. The ends of each wire are then butt welded to each other to close each of the rings and complete the basket. When the basket is completed it is essentially conical in shape, tapering inwardly from top to bottom. The diameters of the circular rings are chosen according to the desired size of the finished basket, with the upper ring having the largest diameter and the lower ring having the smallest diameter. The number of intermediate rings varies according to the size of the basket as does the number of upright loops or members. The baskets can be made in a large variety of diameters, most commonly in the range of from fourteen inches to forty-two inches (diameter of top ring). The angle of the side walls of the basket to the horizontal plane is preferably 75.degree., but other angles in the range of 65.degree. to 85.degree. may be utilized. The upright loops (tree baskets) extend beyond the upper and lower circular rings and are used to attach ropes or twine which lace or tie the tree ball into the basket. As previously mentioned, the use of annealed wire aids in making bends in the loops to adjust the basket and the lacing tightly around the tree ball.
The production methods for both baskets are explained in more detail below, and have been found to be highly improved in efficiency and a significantly more economic means of manufacture.
The objects of the invention therefore include:
1. the provision of an improved wire basket for tree balls;
2. the provision of an improved wire basket which is more easily adjusted or tightened around a tree ball;
3. the provision of a wire tree basket which will quickly corrode and disintegrate after the tree is transplanted;
4. the provision of an improved, efficient and economical method of making wire tree baskets;
5. the provision of a wire basket for supporting tomato plants;
6. the provision of an improved method of producing wire baskets in a variety of sizes; and
7. the provision of an apparatus for welding wire basket flats.